JoVE Encyclopedia of Experiments
Microbiology
0 views • 3:39 min • September 30th, 2026
Begin with an ultracentrifugation tube containing a sucrose gradient.
Carefully add the virus-containing supernatant on top.
Centrifuge with controlled acceleration and deceleration to preserve the gradient, allowing particles to settle into the layer matching their buoyant density during the spin.
Lighter proteins remain in the upper layer. Intact viral particles concentrate between the lower- and higher-density layers, while heavier cellular debris settles at the bottom.
Discard the top layers, and collect the middle, virus-enriched sucrose fractions into a fresh tube.
Add buffer and mix the sample several times.
Next, carefully layer the viral suspension over a low-density sucrose cushion in a fresh tube.
Centrifuge the suspension. Heavier viral particles settle to the bottom, while the lighter contaminants remain in the supernatant.
Discard the supernatant. Drain the remaining liquid by inverting the tube onto a paper towel.
Resuspend the viral pellet in buffer.
The virus-enriched suspension is ready for downstream studies.
Load the conical ultracentrifugation tubes with different sucrose concentrations to form layers with sucrose gradient.
Carefully add the virus containing supernatant to
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